Audience demand meter



April 2, 1946. POTTER 2,397,562

AUDIENCE DEMAND METER Filed Feb. 18, 1944 4 Sheets-Sheet l April 1946. J. T. POTTER 7,

AUDIENCE DEMAND METER Filed Feb. 18, 1944 4 Sheets-Sheet 3 April 2, 1946. 'J. T. POTTER AUDIENCE DEMAND METER Filed Feb. 18, 1944 4 SheetsS1 1eec 4 Jam 7." Par/29? Patented Apr. 2, 1946 UNITED STATES PATENT OFFICE AUDIENCE DEMAND METER John T. Potter, Ma'nhasset, N. Y.

Application February 18, 1944, Serial No. 522,981 3 Claims. (Cl. 234 -76) This invention relates to radio audience meters and, more particularly, concerns a meter for recording the operation of a radio receiver.

The primary object of this invention is to provide a meter which may be installed at or near a broadcast receiver and by means of which, after a period of time such as a few days or a week, it may be ascertained when the receiver was operated, and to which wavelengths the receiver was tuned. Knowing the programs then being broadcast, it is therefor possible to determine the relative popularity of programs by comparing records of the several meters used in a survey.

One of the objects is to provide a meter electronically coupled to a broadcast receiver and responsive to the momentary frequency to which the receiver is tuned. While other receiver outputs might be utilized, it is preferred to derive a signal from the local oscillator of a'superheterodyne receiver, since such a signal bears a constant relationship to the frequency to which the receiver is tuned. Broadly, the meter is intended to include a tunable circuit having one or more variable capacitors, a synchronous electric motor for constantly tuning the capacitor back and forth across a band of frequencies, a recording device including a normally non-marking stylus driven by the motor back and forth across a constantly driven recording medium, and a relay in the output of the tuned circuit so that when the tuned circuit resonates with the receiver output,

the relay actuates the stylus to mark the medium. i

In meters of the present type where a synchronous electric motor is used to drive the recording medium, several difficulties have been encountered, particularly that of power interruption, which ordinarily stops th tape and ruins the time base. By this invention, it is proposed to provide a normally inoperative and normally uncoupled spring clock motor,-a relay in the power circuit for normally disabling the clock motor but which positivel starts the motor upon power interruption, and a one-way clutch for thereupon drivingly connecting the clock motor and tape drive and for simultaneously disconnecting the synchronous electric motor from the tape drive.

Still another object is to provide a combined stylus and capacitor hunting assembly, the elements of which are reciprocated as a unit by the synchronous electric motor only, and which are disabled upon power interruption. Yet again, in the hunting'unit, it is proposed to provide gearing driving th capacitor shaft which may be readily disconnected for indexing.

, connected at I0, ill to chassis i2.

These and other objects will appear from the following specifications and drawings, in which:

Fig. 1 is a diagram of the circuit;

Fig, 2 is a plan view of the mechanical and electrical components;

Fig. 3 is a side elevation partly broken away;

Fig. 4 is a diagrammatic elevation illustrating the hunt assembly;

Fig. 5 is an elevation showing the details as seen from the line 5-5 of Fig. 2;

Fig. 6 shows the detail in elevation as seen from the line 66 of Fi 2;

Fig, 7 shows the detail of the spring clock motor and the disabling and starting mechanism therefor;

Fig. 8 shows in elevation the detail of the gearing between the synchronous electric motor, the spring clock motor, and the tape drive;

Fig. 9 is a section along the line 99 of Fig. 8;

Fig. 10 shows in elevation a detail of the gearing illustrated in Figs. 8 and 9; and,

Fig. 11 is an elevation showing the detail of the tape drive.

Referring now to the drawings, in which like numerals denote like or similar objects, the electrical circuit may best be understood by reference to the diagram of Fig. 1, wherein the input 2 is shown connected to the primary winding 4 adjacent the secondary winding 8 of an input transformer 8, one end of each winding 4 and 6 being It should be understood that input 2is adapted for connection or coupling to a broadcast receiver, and preferably to the output of the local oscillator of a superheterodyne receiver.

. Th non-grounded end of secondary winding 5 is connected to lead I4 of control grid l6 of a pentode I8, and between grid lead it and the chassis at 26 are connected 24 in series the first section 20 of a variable gang capacitor 20 and a fixed capacitor 22, thereby forming with secondary winding 8 a tunable circuit capable of resonating with the input signal. Pentode 88 further includes a suppressor grid 30 connected to the cathode 32 which in turn is connected at 34 through capacitor 86 and resistor 38 to the chassis at 40 and 42 respectively.

The screen grid lead 44 of the pentode is connected to the chassis at 45 through capacitor 48 and through a resistor 50 to one end 52 of the primary winding 54 of a coupling transformer 56, the other end of winding 54 being connected to plate lead 58. Also connected at 52 is the plat power supply line which has in series the winding of relay I26 described below.

One side or secondary winding c2 of transformer 58 is connected st 86 through lead 68 to one side of c rectifier (38, the other side of the winding 82 being connected as shown st it to the chassis and through resistor 712 et it to the other side 01' rectifier 68 at it. Connected across winding 52 are the second section 76 of a variaable gang capacitor 78 and s, fixed capacitor 80 in series as shown at 82, so that relatively shsrply tuned resonant circuits are provided, the recti fied output of which is pessedto an amplifier as follows: capacitor Elli is connected at 86,. 86 between the chassis and the output side or. recti tier 68, which is connected to grid leocl l oi smplii'ier 96; piste power supply is connected by lee-cl {iii to the chassis through resistor C12 which is variably connected at top 08 csthocie leetl tilt.

The output circuit W2 or hes therein the winding of s. stylus reley i65 the out put circuit being adjustable st so 'thst whenever resonance occurs in the prececling tuned circuits, the relay is actuate-i.

Power supply, designated hi8, inclucles the usual power transformer HQ having a piirnsiy winding l l2 adopted. for connection to a 60 cycle domestic power system st MG, anti o secondary winding connected at l-il i for the tube heaters. Plate power is obtained from secondary winding 656 having s inicl top connected by least it to the chassis stool ends connected. to rest er G22, the output of which is connected st iii l power supply line Gil through the winding of clock control relsy B26, both ends of which con" nectecl through capacitors M8 to the chassis so tl'iot when the power supply is on, relay is energized.

Also connected to the domestic power supply at ill lo is synchronous electric motor driving a corn through shaft 3t, whose may best be seen in 2 to 5 inclusive.

Motor tilt clrives' shaft i8 2 through reduction gearing its, the assembly being supported on chassis 62 by brscitets on which sis-o ere mounted guides Mil slidsbly supper rig horison tel rocl M2 cariyirr. intermediate e. com follower wheel i6 3. On the end or" tool [162 is at fixed a leaf spring M6 resiliently rnsintcining the rod i 32 end its related ports upright. R05; i412 rigidly carries a rock its normally meshing with a pinion tilt on short M52 or variable cspsci tors, one. s coil spring I166 has its inner end se cured to shsft tilt and. its outer encl anchored at not to the capacitor frame so that the coin tollower, through pinion Mill, raclr U68, and roe, M2, hereinafter called the hunt assembly, is hissed against cam {132. Finally, the hunt assembly ineludes a spring stylus srin lliil amxeti to rot-l I162 and having a marking element on its free encl. With the arm itz on armature i663 oi reisy loll normally resting lightly on the stylus srrn (168 marking element its reciprocates across the marking tape (later described), and capacitors 20 and it are oscillatingly tuned by the hunting assembly.

The operation of the units thus for described is as follows. Input 2 is coupled to the local oscillator of a broadcast receiver, and power supply leads H4, Ilia are connected to the domestic power circuit which supplies the receiver. Motor I80 starts and drives the hunting assembly to tune capacitors 20, I8 back and forth across their ranges and, of course, to tune the Fig. l circuits continuously. Meanwhile, marking element I80 is likewise being continuously reciprocoted across cosmos the recording tape which is also being driven as hereineiter detailed so that whenever capacitors 20 and. I8 sharply tune their circuits into resonance with the local oscillator, relay I04 is energlzed and arm I162 snaps down for an. instant to actuate marking element iSt. [AS resonance is pafied, spring arm M58 return element I60 to non-marking height. Obviously, the local oscillator will be tuned a predetermined number of cycles off the main tuning of the receiver, for which allowances in calibration may be made. Also, in adjusting the hunting system, rscir i l-8 may be disengaged from pinion its so that the desired indexing of shaft iiiii relative t the remainder of the hunt assembly be eccom pllshed. In summary, every time the capacitors pass resonance with the local oscillators, 9, short inert; will be made at a corresponding piece on the tape and, with the tape being driven at e.

constant speed, a vertical row of merits for a certain ciistence will show that the receiver was tuned to some certain frequency for a corresponding time, and likewise another vertical row spaced laterally ecross the tape will show that the receiver was tuned to another frequency at and for another time.

The tape driving mechanism is arranged so that ordinarily the tape is driven by the synchronous electric motor but, when power interruption occurs, drive is obtained by an otherwise normally inoperative spring clocl: motor. Referrlng now to Figs. 2 and 8 to ll, inclusive, normoi drive is obtained through flexible shaft i coupled through cam [32 to shaft ti t on the other end, through couplings to a worm shalt ill? rotatably mounted by brackets ll to an upright plate N5 of a reel frame il'S so as to mesh withsnd drive gear The i freely l c is rotatable on a transverse shaft 631; as shown best in Fig. 9, the transverse shaft being rotatablymountecl in a. bearing on plate its face, gear [i carries a spring pawl en gsigeeble with the teeth of a ratchet 65-23 rigidly sfi'ixecl on shaft H82 to establish a drivin connection between gear and shaft upon clockwise rotation of gear as seen in Fig. 10, out leaving ratchet and shaft free to ro= tote clockwise relative to gear in which case the gear is locked by worm tlt.

On the inner end of shaft $532 is affixed a pinion not driving a gear G92 cirixeol on the shaft @941 of a toothed spool ltG which, in turn, drives a recording tape its as shown'best in Figs. 3 and 6. Shaft [196i also has afiixed thereon a pulley wheel 296i driving through a coil spring belt M2 an other pulley Zilfl affixed on shaft 2st of a tape take-up reel 2638 which, together with tape-supply reel its, is rotatably supported between vertical plate M2 on. the inside and plates EM, 256 on the outside of frame lit.

- From supply reel 22w, tape 098 is passed over a roller 2I8 where it is supported for marking. While any of the well-known modes of marking may be used, the one illustrated comprises an inked ribbon 220 passing from a supply spool 222 through the upper horizontal slot 22s of slotted guide plate 226, across the tape, around a guide pin 228, back through a lower horizontal slot 230, and to a take-up spool 232. If desired, means may be provided for driving the ribbon, such as a ratchet wheel on the shaft of the take-up spool and a pawl on the armature I64 so that whenever relay I04 is actuated, the take-up spool will be turned, a. short distance. In this example, the marking element I50 is disposed between the upper and lower courses of ribbon 220 so that when the element is snapped down, it will mark the tape.

In case of power interruption, shaft I82 is driven by a spring clock motor 224, the main shaft 236 of which is provided with a cross pin 23! fitting in a key slot 248 in the bars of ratchet I88, as shown in Figs. 9 and 10 so that .when shaft 238 turns, shaft I82 is thereby rotated to drive the tape the same direction and rate as it would be driven by motor I30. However, when the current from the power supply I08 is on, the clock is held in disabled condition by the spring armature 24b of relay I25 which holds the escapement wheel 242 fixed. While clock motor 234 is disabled, the customary slip connection between clock shaft 235 and the remainder of the clock gearing allows the shaft to rotate with ratchet 188 then being driven by synchronous motor 130.

As shown in Figs. 1, 2 and 6, current from power supply i 08 actuates relay i28 so that the spring armature 240 lies in the full-line position with its curved end 244 clamped against escapement wheel 242. However, when the power supply is interrupted, armature 240, fulcrumed at 246, is snapped by spring 248 to its dotted line position, thus freeing escapement 240 and giving it an initial twirl to ensure starting. Thereupon, tape I98 is driven by the clock motor until the electric power goes on, whereupon relay I28 locks the clock and normal drive is resumed.

In the foregoing specification, one proven example of the concept has been detailed. However, the invention ls not to be limited to the specific disclosure, but encompasses the full breadth and scope of the following claims.

I claim:

1. In combination an electric motor, a power supply circuit for said electric motor, a driving element for said electric motor, a driven shaft, a one-way clutch connecting said driving element and said driven shaft, 9. spring clock motor having a drive shaft connected to driven shaft and having a slip connection with the remainder of said spring motor, a relay actuated by said power supply circuit and having an armature frictionally and generally tangentially engageabie with the escapement wheel of said clock motor for holding the same inoperative in response to power in said circuit, and spring means for normally biasing said armature away from engagement with said escapement wheel, whereby to release said. escapement wheel and positively to start the same upon interruption of power in said circuit.

2. The combination claimed in claim 1, said electric motor having a driving shaft and irreversible gearing connecting said one-way clutch and the drive shaft of the electric motor, whereby to prevent rotation of the electric motor drive shaft when said auxiliary motor is driving.

3. The combination claimed in claim 1, said auxiliary motor including a drive shaft connected to the driven shaft and slip-connected to the driving elements therefor, said irreversible gearing comprising a worm gear on the drive shaft of said electric motor, said driving element comprising a pinion rotatably mounted with respect to the driven shaft and meshing with said worm gear, said one-way clutch comprising a pawl and ratchet operatively connecting said pinion and said recording medium shaft.

JOHN T. POTTER. 

